| COAC |
Commercial Customs Operations Advisory Committee (previously, Advisory Committee on Commercial Operations of the Customs and Border Protection) |
| COAST |
Coastal Ocean Assessments, Status, and Trends (unable to verify 5/16) |
| COBRA |
Consolidated Omnibus Budget Reconciliation Act |
| CoC |
Continuum of Care Program |
| COCA |
Clinician Outreach and Communication Activity | Coastal and Ocean Climate Applications (older link archive) |
| CoCASA |
Comprehensive Clinic Assessment Software Application |
| CoCHP |
Coordinating Center for Health Promotion (defunct) |
| CODIS |
Combined DNA Index System |
| COE |
Center for Outcomes and Evidence (merged into CEPI) | Grants Center of Excellence |
| COGH |
Coordinating Office for Global Health (changed to CGH) |
| COL |
Cooperative Oxford Laboratory (older link archive) |
| COLC |
Copyright Office, Library of Congress |
| COMBAT |
Commercial Building Analysis Tool for Energy-Efficient Retrofits (unable to verify 6/19) |
| CONPLAN |
U.S. Government Interagency Domestic Terrorism Concept of Operations Plan (.pdf) |
| CONSER |
Cooperative Online Serials |
| COOL |
Country of Origin Labeling |
| COOP |
Continuity of Operations (older link archive; archive2) | Cooperative Observer Network |
| CO-OP |
Consumer Operated and Oriented Plan |
| CO-OPS |
Center for Operational Oceanographic Products and Services |
| CoP |
Conference of the Parties |
| COPAG |
Cosmic Origins Program Analysis Group |
| COPR |
Council of Public Representatives (unable to verify 11/14) |
| COPS |
Office of Community Oriented Policing Services |
| COPs/ROPs |
Country Operational Plans (older link archive) |
| COR |
Cosmic Origins Program |
| CORAL |
COral Reef Airborne Laboratory |
| CORD |
CDC Online Resource Directory (unable to verify 12/18) | Childhood Obesity Research Demonstration |
| CORE Network |
Coordinated Outbreak Response and Evaluation Network (older link archive) |
| Core SVIPP |
Core State Violence and Injury Prevention Program |
| Core VIPP |
Core Violence and Injury Prevention Program (changed to Core SVIPP) |
| CoRIS |
Coral Reef Information System |
| CORP |
Corporation for National and Community Service |
| CORS |
Continuously Operating Reference Stations |
| CoS |
NSTC Committee on Science (defunct or inactive 1/17, WH transition) |
| COS |
Report of Organization |
| COSIM |
Climate, Ocean and Sea Ice Modeling (unable to verify 12/16) |
| CoSTEM |
NSTC Committee on Science, Technology, Engineering, and Math Education (defunct or inactive 1/17, WH transition) |
| CoT |
NSTC Committee on Technology (defunct or inactive 1/17, WH transition) |
| COTPER |
Coordinating Office for Terrorism Preparedness & Emergency Response (defunct) |
| COTS |
Cotton, Oilseeds, Tobacco and Seeds Division (unable to verify 12/13) |